Hey People! I was bored last night so I made this Stock Submarine with Mk2 Parts and a re-usable Missile bay. I would put it in the water using hack gravity. I am working on some other missiles, a missile boat, and an aircraft carrier. I'll post those later. I have not tested it that much, the most I've gotten to was 5 m/s in the water. In KSP 1.1.5
1 toggles dive motors, 2 toggles ascent motors, 3 toggles forward motors, 4 toggles reverse motors (Use sparingly), 9 toggles bay doors, 0 launches missile.
https://www.dropbox.com/s/leh8vt38wzsjfgs/MS-10.craft?dl=0